A concealed type slide fastener includes a type in which fastener elements are attached on a fastener element attaching portion formed on a side edge portion of a fastener tape created by knitting or weaving in advance, by sewing or molding, and a type in which at the same time when a fastener tape is knitted or woven, a continuous fastener element row composed of synthetic resin monofilament is fixed on a fastener element attaching portion by knitting or weaving.
For example, in case of the knitted concealed type slide fastener, at the time when a warp knitted tape having a fastener element attaching portion and a tape main body is formed by knitting, monofilaments made of synthetic resin in which coupling heads are molded in advance by stamping processing are warp-inserted continuously such that its upper/lower leg portions are arranged neatly in line, so that the continuous element row is knitted into the fastener tape.
In case of an ordinary knitted slide fastener, a continuous fastener element row is knitted in such that respective coupling heads are projected outward from an outside end of a fastener element attaching portion while each connecting portion for connecting upper/lower leg portions is disposed on a boundary portion on a tape main body. However, in case of the concealed type slide fastener, as disclosed in for example, Japanese Patent Application Laid-Open (JP-A) No. 8-228813, coupling heads of fastener elements are disposed along a bending region which is a boundary portion between a tape main body and a fastener element attaching portion, and a connecting portion is disposed along the outside end of the fastener element attaching portion.
A concealed type slide fastener stringer obtained by such knitting is folded along the bending region such that the fastener element row is exposed to the outside and set up, and the folded condition is fixed. With fastener elements of right and left stringers whose folding condition is fixed, meshed with each other, a fastener chain is produced. After a slider for the concealed type slide fastener is attached on the fastener chain, it is cut to a predetermined length and top and bottom end stops are attached, thereby finally producing a concealed type slide fastener which is a final product. Because the concealed type slide fastener is sewed on clothes with its fastener element row set inside, the fastener element row is not seen from outside.
According to FIGS. 24 and 25 in the JP-A No. 8-228813 (patent document 1) and corresponding description thereof, the upper leg portion and the lower leg portion are arranged neatly in their vertical relation by reciprocating monofilament which forms a coil-like fastener element row within the same course. In addition, with the coupling heads disposed near the inside end of the fastener element attaching portion and the connecting portion disposed near the outside end of the fastener tape, the upper/lower leg portions are pressed with three fixing chain yarns 10 which knit with a double structure by weft-insertion and at the same time when the fastener tape is knitted, the coil-like fastener element row is fixed on the fastener element attaching portion.
On the other hand, the woven concealed type slide fastener has been disclosed in, for example, Japanese Utility Model Application Laid-Open No. 2-132419 (patent document 2), JP-A No. 2-283306 (patent document 3), JP-A No. 9-234103 (patent document 4) and the like. In any case, at the same time when a fastener tape having a weaving structure is formed by knitting, a monofilament made of synthetic resin whose coupling heads are molded in advance is woven continuously into the fastener element attaching portion of the fastener tape.
Meanwhile, different from a type in which fastener elements are fixed on the element attaching portion of the fastener tape by sewing, caulking or molding the fastener elements, usually, the above-described knitted/woven concealed type slide fastener often contains no core thread at the element attaching portion of the fastener tape. This core thread is knitted or woven by being inserted in the warp direction from the side edge of the element attaching portion when the fastener tape is knitted or woven. By sandwiching the core thread knitted or woven in this way between the upper and lower leg portions under a pressure, the respective elements are fixed firmly on the fastener tape, so as to keep the fastener elements from slipping out of the fastener tape.
In case of the knitted/woven concealed type slide fastener, if it is intended to knit or weave the core thread into the fastener tape, a special mechanism for knitting or weaving the core thread is necessary as disclosed in the above-described patent document 4, thereby complicating the structure of a knitting machine or weaving machine. The knitted/woven concealed type slide fastener of this type has been originally developed to intensify fashion performance without deteriorating its appearance of an outer garment or the like, and in recent years, has been often employed by thin clothes having ample plasticity. In order to sew the knitted/woven concealed type slide fastener on this kind of thin clothes, it is desirable to form the fastener tape itself into a thin and plastic structure and at the same time, eliminate gaps between the upper and lower leg portions of the fastener element itself, so that the upper and lower leg portions are fitted to each other if possible so as to reduce the entire thickness of the concealed type slide-fastener. However, existence of the core thread is opposite to these demands.
Further, if the core thread is eliminated, it comes that the fastener elements are only fixed with an element fixing (tightening) warp knitting yarn or warp weaving yarn disposed at the element attaching portion. As a consequence, as described above, the attaching position of the fastener elements changes on the fastener tape, so that the position of the coupling head becomes likely to deflect in the tape width direction of the fastener tape. Thus, the arrangement position of the coupling heads likely becomes uneven. This is fatal for the concealed type slide fastener whose purpose is to inhibit the coupling state of the coupling heads from being seen from outside of an attaching object when the slide fastener is closed.
On the other hand, when this kind of concealed type slide fastener is sewed on an attaching object, in case of the knitted concealed type slide fastener, it is sewed along a bending portion of each fastener element row of its right/left stringers, that is, a groove formed between two wales adjacent to the coupling head of each fastener element row. In case of the woven concealed type slide fastener, it is sewed to an attaching object along the bending portion of each fastener element row of the right/left stringers, that is, along multiple warp yarns adjacent to the coupling head of each fastener element row.
When the slide fastener is closed in case of an attaching object on which stringers of right and left slide fasteners are attached with a sewing thread, if right and left attaching objects are pulled strongly in a departing direction, loops of the sewing thread are pulled together with the attaching object. As a consequence, the loop positions of right and left sewing threads deflect across a groove stretching in the wale direction of the right and left stringers of the sewed slide fastener or in the departing direction of the weft yarns located between warp yarns at a sewing position, so that a gap is generated between the right and left attaching objects and the stringers, thereby often the coupling heads of the fastener elements being seen from outside.
The present invention has been accomplished to solve the above-described problem, and a specific object of the invention is to provide a knitted or woven concealed type slide fastener in which continuous fastener elements are knitted or woven at the same time when a fastener tape is knitted or woven, wherein coupling portions of fastener element rows are not seen through between attaching objects from outside when the slide fastener is closed, and more particularly to a concealed type slide fastener having ample function as a concealed type slide fastener capable of securing a required mounting strength to the fastener element row even in a thin and highly plastic fastener tape.